And no, it is not fake, the the making of will attest:
The official site is http://walkmanproject.com/ which has the add and the making of (if they dissappear from youtube). Interestingly, the official website is also encouraging everyone to contribute their own tracks, mix up other people's tracks and rate other people's mixes...
Keywords: ad campaign, advertising, collaborate, collaboration, community, jamm, mix, orchestra, rate, sony, unusual, walkman